DE 10 2007 057 984 A1 discloses such a transfer gearbox in which an oil reservoir is provided for collecting the lubrication oil conveyed by means of the chain. The oil spun off from the chain is accommodated in the oil reservoir and conducted from there via a metering device to a friction clutch. After performing the lubrication and cooling function, the lubrication oil flows from the friction clutch back into the oil sump.
One disadvantage of known transfer gearboxes lies in the fact that the lower chain wheel which engages in the oil sump and the chain guided through the oil sump bring about undesirable churning losses, i.e. as a result of drag torques which occur in the oil sump, the efficiency of the transfer gearbox is reduced. Moreover, as a result of this, the temperature of the lubrication oil located in the oil sump is increased so that the cooling action of the lubrication oil is reduced.